Not Applicable.
Not applicable.
As is know in the art, there has been a trend to include detectors in vehicles, such as automobiles. It is necessary to provide a detector that is capable of accurately and reliability detecting objects in the path of the vehicle. Such a detector is sometimes referred to as a Side Object Detection Sensor (xe2x80x9cSODSxe2x80x9d) and must be relatively insensitive to the relative location of the automobile and obstacles and environmental conditions, such as temperature, humidity, ice and rain.
Radar is a suitable technology for implementing an automotive SODS. One type of radar suitable for this purpose is Frequency Modulated Continuous Wave (FMCW) radar. In typical FMCW radar, the frequency of the transmitted CW signal linearly increases from a first predetermined frequency to a second predetermined frequency. FMCW radar has the advantages of high sensitivity, relatively low transmitter power and good range resolution.
Because the SODS is a consumer product which may affect the safety of vehicles, the accuracy and reliability of the sensor are tantamount. Aspects of the SODS which contribute to its accuracy and reliability include its susceptibility to noise and the overall precision with which received radio frequency (RF) signals are processed to detect objects within the field of view of the SODS. Susceptibility to noise for example can cause false detections and, even more deleteriously, cause an object to go undetected.
Further significant attributes of the SODS are related to its physical size and form factor. Preferably, the FLS is housed in a relatively small enclosure mountable behind the forward surface of the vehicle""s engine housing, or grill. For accuracy and reliability, it is imperative that the transmit and receive antenna and circuitry are unaffected by attributes of the vehicle grill and are mounted to the vehicle in a predictable alignment.
Also impacting the accuracy and reliability of the SODS is the existence of foreign matter or objects which undesirably block one or more portions of the SODS transmit and/or receive antennas and in particular block portions of the RF energy propagating to and from the SODS transmit and receive antennas. Such blockage, can be caused by an accumulation, over a period of time, of foreign matter or objects in the region of the antenna aperture. Such foreign matter may be caused for example by environmental conditions such as temperature, humidity, ice, rain and the like. Such blockage can degrade, or in extreme cases even prevent, proper operation of the SODS. Once a vehicle in which an FLS is mounted is deployed on the road, a gradual, continual accumulation of foreign matter can occur. This results in a corresponding gradual decrease in SODS system performance thus making it relatively difficult to detect the existence of antenna blockage sue to gradual accumulation of foreign matter.
It would, therefore, be desirable to provide an SODS which is capable of detecting antenna blockage. It would also be desirable to provide an SODS which is capable of detecting antenna blockage due to the accumulation of foreign matter, such as mud, ice, snow or the like, on the vehicle on that area of the vehicle in which the SODS is mounted. It would further be desirable to provide an SODS which detects antenna blockage and which alerts a system user of the existence of such blockage.
In accordance with embodiments of the present invention, set forth is a system for detecting antenna blockage of a radar system, such as a SODS mounted on an automobile. The system for detecting antenna blockage of the radar system includes a blockage detection processor adapted to receive a plurality of signals provided by a signal processor included on the radar system or by external sources to detect a blocked condition of the antenna of the radar system. In an embodiment, the blockage detection processor includes a vehicle speed input, sensor temperature input and pattern recognition information input.
In one aspect of the present invention, a method of operating the system for detecting antenna blockage in a radar system, which includes a transmit antenna and a receive antenna, includes sensing a first leakage signal communicated between the transmit and receive antennas and comparing the energy level of the first leakage signal to at least one of a number of predetermined pattern recognition profiles. The method further includes determining if the first leakage signal substantially matches predetermined characteristics of any one of the number of predetermined pattern recognition profiles. If it is determined that the first leakage signal substantially matching the predetermined characteristics of any one of the number of predetermined pattern recognition profiles, the system generates a first signal having a first value corresponding to an antenna blockage. If it is determined that the first leakage signal does not match the predetermined characteristics of any one of the number of predetermined pattern recognition profiles, the system generates a second signal having a second value corresponding to an absence of antenna blockage.
The method further includes determining if the energy level of the first leakage signal deviates from a predetermined leakage signal threshold level. If the first leakage signal deviates from the predetermined leakage signal threshold level, the system generates the first signal. Furthermore, if the first leakage signal does not deviate from the leakage signal threshold level, the system generates the second signal.
In another aspect of the present invention, the method further includes determining if the energy level of the first leakage signal deviates from a predetermined leakage signal threshold level. If it is determined that the first leakage signal deviates from the predetermined leakage signal threshold level, the system generating the first signal. Further, if the first leakage signal does not deviates from the leakage signal threshold level, the system generates the second signal. The above described method can be cyclically repeated a predetermined number of times to generate a plurality of the first signals and a plurality of the second signals. After generating the plurality of the first signals and the plurality of the second signals, the method further includes determining if a predetermined number of the first signals are present. If it is determined that the predetermined number of the first signals are present, the system generates an antenna blockage detection signal.
The method of comparing the energy level of the first leakage signal to at least one of a number of predetermined pattern recognition profiles, as described above, further includes comparing the energy level of the first leakage signal to at least one of a number of predetermined pattern recognition profiles previously stored in a database. The predetermined pattern recognition profiles, which are stored in the database, represent signatures associated with a plurality of different objects likely to block the antenna causing the antenna blockage.
The method of comparing the energy level of the first leakage signal to at least one of a number of predetermined pattern recognition profiles, as described above, further includes comparing the energy level of the first leakage signal to at least one reference leakage signal profile previously stored in the database. The reference leakage signal profile represents a leakage signature generated in the absence of antenna blockage.
The method of generating the antenna blockage signal, as described above, further includes generating a plurality of first values associated with each of the plurality of first signals, which represent a presence of an antenna blockage. Furthermore, the method includes generating a plurality of distance values, which are associated with each of the plurality of first signals. The distance values represent a distance between the antenna and an object associated with the blockage.
The method of determining if a predetermined number of the first signals are present includes sensing a velocity signal associated with relative motion of the antenna. If the plurality of distance values, as described above, are substantially equivalent during the sensing of the velocity signal, the system generates the antenna blockage detection flag.